Why can’t my students reply to my post on a forum or make their own post?
You may be using the “News forum”, which only allows you to post announcements for your students to view. For this reason, the MC universal template provides a “Ask the Instructor” forum, where students can ask course-related questions, and you reply. For more information on the MC campus-wide template, view here.
If they are unable to comment on a regular forum you have created for them, you may have set an open and close date for the forum, in which case would block students from posting after the due date.